Research progress on improving the freeze-drying resistance of probiotics: A review

In recent years, as the beneficial effects of probiotics have been gradually discovered, the use of drying methods to stabilize probiotic ingredients has been more deeply applied to food, medicine, and other fields. The probiotic powder obtained by freeze-drying can effectively maintain the viability of probiotics and has good fermentation performance. Freeze-drying of probiotics allows the strain to maintain its original chemical composition and physical properties, and the energy consumption is lower than other drying methods. This is also a promising way for long-term storage of probiotics and satisfies more possible fermentation applications. This review mainly introduces the effect of freeze-drying process on probiotics and proposes some key strategies that can effectively improve the viability of probiotics after freeze-drying, such as changing the culture conditions and media components of the strain, adding cryoprotectants, etc. The future application of freeze-drying to prepare probiotic microbe powder is also prospected.